U.S. Pat. No. 4,450,755 which issued on May 29, 1984 discloses a blower apparatus which is especially suitable for the generation of an air curtain, screen or barrier. The apparatus described in this patent includes a blower having a plurality of blades arranged in cylindrical disposition. A guide encircles the blower but extends axially beyond the blower to provide for the generation of an air stream, the width of which is greater than that of the blower. A deflector or interceptor plate in the form of a scroll is arranged to prevent air from circulating in axial direction back into the blower and is provided to improve the effectiveness of generation of the air stream which flows tangentially out of the blower apparatus through a vent through which the air stream is discharged.
It has now been found that it may be desirable to control the flow of the air discharged through the abovementioned vent as well as in other type of apparatus. Such ability provides for a more particular control of the disposition of the air curtain and also provides for situations wherein the vent in the blower apparatus may not be appropriately arranged to direct the air curtain in a particularly desired direction. For this purpose it has been found, in accordance with the present invention, that it is desirable to provide a plurality of adjustable louvres at the abovementioned vent to provide for the control of the flow of air therethrough.
Venting arrangements have long been known and some of these arrangements are shown by way of example in U.S. Pat. Nos. 1,725,353; 1,753,587; 1,872,794; 3,180,246; 3,270,657; and 3,601,034.
In U.S. Pat. No. 1,725,353, R. M. Hinrich discloses an adjustable air diffuser in which an arrangement is provided for retaining each of a plurality of blades in different positions of adjustment independently of the other blades. For this purpose elongated loops are pivotally connected to the blades and are held by a clamping arrangement associated therewith. Such an arrangement results in the accumulation of dirt and grime at a location whereat these contaminants are prevalent.
F. M. Young discloses in U.S. Pat. No. 1,753,587 the use of air deflectors adjustably mounted to control the flow of a current of air which has been impelled by a fan propeller. These deflectors are mounted at one of their edges and can be adjusted in order to control the flow of air. The nature of the adjustment is not set forth in any detail and appears to be a simple matter of manual control.
In U.S. Pat. No. 1,872,794, Q. G. Noblitt et al illustrate a plurality of pivotally mounted shutters. These shutters are utilized to direct air flow. These shutters appear to be manually controllable and no description is offered of the manner in which these shutters are fixed in position.
In U.S. Pat. 3,180,246, E. H. Johnson reveals an air control device such as a diffuser or the like. Therein are provided a number of shutter arrangements in which provision is made for rotational adjustment of the same. To retain the blades in their positions a frictional device is employed involving the use of a pressure plate. As will become apparent hereinafter such an arrangement is substantially different from what is offered in accordance with the present invention.
In U.S. Pat. No. 3,270,657, R. C. Jaye shows an air outlet having angularly adjustable louvres. The louvres are adjustably accommodated in receptacles wherein they are retained by a friction fit which is enhanced by the particular construction of the louvres.
In U.S. Pat. No. 3,601,034, J. Thorne reveals a diffuser having a frame made of L-shaped members with a plurality of louvres extending between the L-shaped members. The louvres have pins extending through openings in the frame members with resilient fingers engaging the louvre pins and securing the louvres against inadvertent rotation thereof.
None of the aforesaid louvre arrangements nor any other structures known to me are anticipatory of the concept developed in accordance with the invention and described hereinbelow.